Electric gating device



Nov. 28, 1961 s. DUINKER 3,011,064

ELECTRIC GATING DEVICE Filed March 15, 1957 VEN TOR. SIMO UINKER BY ra 2.;

United States Patent ELECTRIC GATING DEVICE Simon Duinker, Eindhoven, Netherlands, assignor to North American Philips Company, Inc., Irvington on Hudson,N.Y. a v Filed Mar. 13, 1957, Ser. No. 645,687 I Claims priority, application Netherlands Apr. 11, 1956 Claims. (Cl. 307-88) brought into a magnetic field and, by means of opposite electrodes, an electric current is passed through said plate transversely and preferably substantially at right angles to said field,j an electric voltage is set up between .two further electrodes, the path between the last-mentioned electrodes being transversely and preferably substantially at right angles to the magnetic field and to the path between the two first-mentioned electrodes. Certain ma- 7 terials, for example bismuth or indium-antimony, have another remarkable effect, the so-called magneto-resistanceetfector Gauss effect. If a magnetic field is applied transversely'to. a plate of such material and an electric current between two opposite electrodes is passed through said plate transversely to the magnetic field, it is found thatthe resistance between said electrodes varies with the value of the magnetic field. This effect increases inintensity when the'temperature decreases and from a given value of the magnetic field the relationship between the resistance of the plate and the magnetic field is substantially linear.

The object of the invention is to utiilze the described effects for building up a suitable electric gating device which exhibits memory and, if desired, amplifying properties owing to the use of said magneto-electric transmission properties in conjunction with a soft magneticmaterial of considerable remanence.

The gating device according to the invention is characterized in that it comprises a core consisting of soft magnetic material of considerable remanence, for instance a square loop ferrite material known under the trademark Ferroxcube, which core is surrounded by at least one control winding, means by which a remanent induction produced by said control winding may be supressed at least substantially, and at least one plate of a material having magneto-electric transmission properties, which plate is arranged in a comparatively narrow air-gap of,

for instance, 0.1 mm. width in said core and is provided with at least one pair of electrodes which are coupled to a pair of terminals of the device and arranged on opposite lateral faces of the plate, in such manner that the direction of any magnetic field occurring through the core and the plate is transverse to the direction from one electrode to the other and to the main faces of the plate, so that the transmission of an electric signal via the plate to said pair of terminals is dependent upon the magnetic flux through the core and the plate.

In order that the invention may be readily carried into effect, several embodiments will now be described, by way of example, with reference to the accompanying drawing, in which:

FIG. 1 shows a first embodiment of an electric gating device according to the invention.

FIG. 2 shows the plate and the input and output circuits of this embodiment.

FIG. 4 shows the plate and the energizing and output circuits of the second embodiment.

FIG. 5 shows a third embodiment.

FIG. 6 shows the plate and the input and output circuits of the third embodiment.

. FIG. 7 shows a fourth embodiment. FIG. 8 shows the plate and the input and output circuits of the fourth embodiment.

FIG. 9 shows a fifth embodiment, and

FIG. 10 shows the plates and the input and output circuits of the fifth embodiment.

The embodiment shown in FIGS. 1 and 2 comprises a core 1, 1, made of a soft magnetic material of considerable remanence, for example Ferroxcube or another soft ferrite with substantial remanence. This core has the form of a ring consisting of two parts, the part 1 constituting three quadrants and the part 1' approximately one quadrant of the ring, a narrow air-gap remaining between'the parts 1 and 1'. The faces of the two parts 1 and 1' which contact with one another and with a thin plate 2, arranged in the air-gap, are substantially at right angles to one another, so that the correct position of the part 1' with respect to the part 1 and the plate 2 may be adjusted by means of displacement along the separating surface between the parts 1 and 1', and an additional airgap between said parts or between each of said parts and the plateZ does not exist. The part 1 has formed in it a FIG. 3 shows a second embodiment of the gating device.

hole 3, by which it is split into two branches of equal cross-section through part of its length and in the direction of any magnetic field occurring. Each of said branches is surrounded by an erasing winding 4, by means of which the two branches may be magnetized simultaneously and in opposite directions. Consequently, an apparent additional air-gap is introduced into the annular core, which air-gap substantially eliminates any remanent magnetic induction of the whole core. A control winding 5 surrounds the whole cross-section of another part of the core 1, '1. A current traversing this winding produces a mag netic field throughout the core and, since this core is made of a material having considerable remanence, a considerable remanent magnetic induction subsists in the core and sets up a corresponding field through the air-gap. The plate 2 is ground from a germanium crystal and thus exhibits the so-called Hall effect. Two pairs of electrodes 6, 6' and 7, 7' are arranged on its side-faces (FIG. 2). The direction from the electrode 6 to the electrode 6 is substantially at right angles to the direction from the electrode 7 to the electrode 7 and both directions are substantially at right angles to the direction of a magnetic field through the plate, which is produced by the remanent magnetic induction, if any, of the core 1, 1'.

The electrodes 6, 6' and 7, 7 are connected to two input terminals 9, 9' and two output terminals 10, .10 respectively. The winding 5 is fed with control pulses originating from a control pulse source, the winding 4 being connected to a source of erasing pulses.

When the winding 5 receives a control pulse, the core 1, 1 is magnetized, so that a magnetic field is set up through the plate 2 substantially at right angles to the direction of an input current flowing between the electrodes 6 and 6. Consequently, a voltage substantially proportional to the input current flowing between the electrodes 6 and 6' is set up between the terminals 10 and 10.

transferred to the terminals 10 and 10. Since the core 1, 1 consists of a material with considerable remanence, a short control pulse sufiices to bring about the transmission between the terminals 9, 9 and 10, 10'. This core thus fulfills the function of a memory which recalls hav- So long as the plate 2 is submitted to the action of the magnetic field through the core 1, 1' input sig-, nals applied between the terminals 9 and 9 are thus ing received a control pulse. However, the remembrance of this control pulse is erased as soon as an erasing pulse of arbitrary polarity or even an alternating-current pulse is supplied to the winding 4. The maximum amplitude of this erasing pulse must be sufiiciently high to saturate in opposite directions the two branches of the split portion of the core 1, 1. With respect to the remenent magnetic induction of the whole core, this portion of the core 1, 1' thus behaves during the erasing pulse as a comparatively broad additional air-gap, so that the remaining field through the corel, 1' and the plate 2 greatly decreases. Since the plate 2 is no longer traversed by a noticeable magnetic field, it loses its transmission properties based on the Hall effect, so that the signal applied to the terminals 9 and 9' is no longer transferred to the terminals 10 and 10'.

It might be sufiicient to wind the winding 4 on only one of the branches of the split portion of the core 1, 1. In fact, the magnetic reluctance of the path through the two branches of this portion is much smaller than that through the whole core, which also comprises an airgap, it but a small one.

FIGS. 3 and 4 show a second embodiment which comprises a core 1, 1' of soft magnetic material with considerable remanence, a Hall plate 2 and windings 4 and 5, like the first embodiment. The core 1, 1' has the same shape as in the first example and the plate 2 is likewise arranged in a narrow air-gap of this core, which is provided with a hole 3, through which the winding 4 is wound. As may be seen from FIG. 4, the electrodes 6 and 6 of the Hall plate are, however connected directly to the terminals of an energizing current source 8 and the input terminals 9 and 9 are connected to an input winding 11, which also surrounds the core 1, 1' (FIG. 3). A current traversing this winding brings about a variation in the magnetic flux through the Hall plate 2, the output voltage at the output terminals 10 and 10' varying in accordance with this flux variation.

This embodiment can work in the manner described hereabove so long as the core 1, 1 is not brought into a saturation range by the control pulses and so long as it exhibits sufficient permeability at the work-point determined by the ampere turns of the control pulse.

The third embodiment shown in FIGS. and 6- is a so-called gyrator gating device, that is to say that a transmission in a given direction, for example in FIG. 6 from the left to the right may be brought about, via the Hall plate 2. by means of a first winding 5, which receives control-pulses from a first control pulse source, while pulses from a second control pulse source can be supplied to a second control winding 5' in order to bring about a transmission in the reverse direction. This gating device also comprises an erasing winding 4, which is wound through a hole 3 of a split portion 1 of the core ll, 1. The core 1, 1' comprises a part 1 in the form of a half ring, in which the hole 3 is provided, and a rod-shaped part 1', the ends of which are opposite the end surfaces of the half ring 1. The Hall plate 2 is arranged between one end surface of the half ring 1 and one lateral face of the corresponding end of the rodshaped part 1', this end surface of the half ring I having been ground off through a thickness equal to that of the plate 2, so that there remain substantially no air-gaps between the contact faces of the parts 1 and 1 and of the Hall plate 2. The Hall plate 2 is provided with two pairs of electrodes 6, 6 and 7, 7' of equal surface-areas, which are so arranged that the paths between the electrodes of each pair of electrodes are equal to one another and that the directions from one electrode to the other of each pair of electrodes are at right angles to one another and to the direction of any magnetic field occurring through the air-gap of the core 1, 1. The network including the electrodes 6, 6 and 7, 7' also comprises two resistors 12 and 12, by which the electrodes 6, 6 are connected to the electrodes 7, 7. The Hall plate 2 has a square shape and the resistors 12 and 12 are equal to one another.

In the absence of a magnetic flux through the Hall plate 8, this plate constitutes a passive element in the network between the pairs of terminals 9, 9' and 10, 10'. Under these conditions, a transmission may take place through said network in either direction, the resistors 12 and 12 and the resistances between the electrodes of the plate 2 bringing about an attenuation of the signal transmitted. A flux of a given direction may be produced byv means of a short control pulse through the winding 5, while a flux of opposite direction may be produced by means of a control pulse of the same polarity through the winding 5. The resistors 12 and 12' have a value such that the presence of a magnetic flux through theplate 2 improves the transmission in a given direction, for example from the left to the right, by approximately 6 db and substantially suppresses the transmission in the opposite direction. This is attributable to the fact that the transmission in the first direction resulting from the Hall effect is in phase with the trans-mission through the resistors 12 and 12, whereas in the second direction the transmission through the Hall effect counteracts the transmission via said resistors.

The remanent magnetic induction of the core 1, 1' may be substantially eliminated by means of an erasing pulse applied to the erasing winding 4. Flll'th6I'IIlOl'6,'it would, of course, be possible to utilize only one control winding and vary the direction of the transmission by supplying control pulses of opposite polarities to this winding.

The gating device above described is equivalent to a switch by which the trans-mission in one direction or in the other may be prevented, which switch may be changed-over to one or the other of its set positions or to its reset position by means of short control or erasing pulses and remains in the selected position until it receives a new control or erasing pulse. A new control pulse producing a magnetic flux of the same direction as that of the preceding control pulse, or a second or further erasing pulse is, however, of no consequence for the gating device.

FIGS. 7 and 8 show a fourth embodiment comprising a so-called or gating device. By means of a first control winding 5, arranged on a core 1, 1 of a soft magnetic material with considerable remanence and connected to a first control pulse source, it is possible to produce a magnetic flux through the core 1, 1, so that a transmission takes place from the terminals 9, 9 to the output terminals 10, 10. A second control winding 5 is arranged on the core 1, 1'. This winding is connected to a second control pulse source, so that a transmission from the terminals 9, 9' to the terminals 10, 10' may also be brought about. The part 1 of the core 1, 1' is provided with two holes 3 and 3', through which two erasing windings 4 and 4 are wound. The core 1, 1' comprises two L-shaped portions 1 and 1. The portion 1' has limbs shorter than those of the portion 1, so that the contact faces of the two portions and the contact faces of these portions with a plate arranged between them are at right angles to one another. It is thus ensured that there remain substantially no air-gaps between the faces of the two core portions 1 and 1 which contact with one another and with the main surfaces of the plate.

The plate might be a Hall plate with two pairs of electrodes connected in the manner shown in FIG. 2. However, in this embodiment, the Hall plate is replaced by a plate 13 consisting of a material, for example bismuth or an indium-antimony alloy, having a considerable socalled magneto-resistance effect or Gauss eliect. The plate 13 is provided with a pair of electrodes 14, 14 and is included in an electric bridge circuit, as shown in FIG. 8. The bridge circuit of FIG. 8 includes the resistance of the plate 13 between the electrodes 14 and 14' and further resistors 15, 16 and 17. Two diametrically opposite points of the bridge are connected to the input terminals 9 and 9' via an energizing current source 8, while the two other However, whena magnetic as a result of thedisturb-ance in the balanced condition of the bridge. 'The resistance of the plate 13 between the terminals 14, .14 increases with the magnetic flux, result ing in said disturbance of the balancedcondition of the bridge. With comparatively high field strengths this increase in resistance is proportional to the field strength of the magnetic flux and is much greater at a low temperature than at room temperature. 7 Consequently, it is advantageous for the core 1,1 with the windings 5, 5, and 4, 4. and the plate 13 to be arranged within a cryostat and maintained at a low temperature, for example at the temperature of liquid air. In this manner, it is possible achieve satisfactory transmission and save one or more amplifier stages. The magneto-resistance effector Gauss effect isstrong- .est if the direction of the magnetic flux is at right angles to the main faces of the plate 13 andhence also to the direction from one of the electrodes 14 and14 to the other and it is substantiallyindependent of reversal of the direction of this magnetic flux.

. The useful output-power of a plate with magneto resistance effect is proportional to the direct-current power delivered by the energizing current source, which is thus chosen as .high as possible,,making allowance for the maximum permissible powerdissipationin the plate. The terminals 9, 9' are therefore connected to a signal sourceof low direct-current resistance, for example to the secondary winding of a transformer. In one modificationofthis embodiment, the energizing current source 8 is connected directly to the electric bridge, the inputterminals9, 9' being connected to an input winding such as Ithe'winding 11 of FIG. 3. The input-power thus brings about variations in the magnetic flux through the plate13 and corresponding variations in the resistance of this plate.

Control pulses of arbitrary polarity supplied to one or the other of the control windings 5 and 5' can thus bring about a transmission from the terminals 9, 9' to the terminals 10, 10' whereas erasing pulses supplied to one or the other of the erasing windings 4 and 4 can suppress this transmission by magnetically saturating one of the split portions of the core part 1.

In each of the embodiments above described, it would be possible to arrange a second plate 2' or 13' between the parts 1 and 1' of the core, as shown in dotted lines in FIGS. 1 and 7. The paths between the electrodes of corresponding pairs of electrodes of these plates would then be connected in series with one another.

FIGS. 9 and 10 show a fifth embodiment in which the gating device constitutes an and circuit. This embodiment comprises two three-limbed cores 20, 20', 20" and 21, 21', 21" and two Hall plates 2 and 22. The portions 20 and 21 of each of these cores are L-shaped and provided with two holes 3 and 3', through each of which an erasing winding 4, 4, respectively is wound. The portion 20', 21 respectively of each core constitutes the centre limb of this core. It is smaller than the portion 20, 21 respectively and is also L-shaped,so that one of its end surfaces engages the inner lateral face of one end of the portion 20, 21, respectively, whereas its other end surface is opposite the inner lateral face of the other branch of the portion 20 and 21, respectively, and the Hall plate 2 and 22, respectively, is arranged between this end surface and this inner lateral face. The end surfaces 6 of the portions 20, 21' respectively and the inner lateral faces of the portions 20, 21 respectively being at right angles to one another, there subsists substantially no airgaps between these portions, nor between these portions and the main faces of the corresponding Hall plate. The third portion 20", 21", respectively, of each core is also L shaped and substantially of the same size as the corresponding portion 20 or 21'. The end faces of these third portions 20" and 21" engage the outer lateral face of the corresponding portions 20, 21 and the inner lateral face of the end of the branch of the. portion 20', 21 respectively,

in which the holes 3, 3 respectively are provided. The

contact faces of the portions 20, 20 and21, 21', respectively, with the third portions 20 and 21" being at right angles to one another, there subsists substantially no airgaps between'the portions 20", 21", respectively, and the two other portions of the corresponding core. A control winding 5,5, respectively, is provided on the centre limb of the core 20, 20', 20" and the core 21, 21, 21" respectively. The holes 3, 3, respectively, with their windings 4, 4', respectively, are located on each side of the Hall plate 2 or 22 and in a segment of the portion 20 or 21'of the corresponding core which is located between the lefthand and the right-hand outer limb, respectively, and the centre limb of this core. i

Thewindings 5 and 5 are connected to two different control-pulse sources. The erasing windings 4 of the two cores are connected in series with one another and to a first erasing pulse source, while'the erasing windings 4 are likewise connected in series with one another and to a second erasing pulse source. V The two Hall plates 2 and 22 are connected in cascade with one another. The plate 2 is provided with two pairs of electrodes 6, 6' and 7, 7, which are connected in the manner shown in FIG. 2. Plate 22 is likewise provided with two pairs of electrodes 26, 26' and 27, 27'. The electrodes 26. and 26' are connected to the output terminals 10 and 10' of the network of the Hall plate 2, while the electrodes 27 and 27' are connected to output terminals 30 and 30' of the gating device. A signal applied to the input terminals 9 and 9 can be transmitted to the output terminals 30 and 30' only if both Hall plates 2 and 22 are submitted to the action of a magnetic flux. If only the plate 2 is submitted to the action of such a flux, the signal is transferred to the terminals 10 and 10 but cannot reach the output terminals 30 and 30", since no Hall voltage is set up across the plate 22. Conversely, the signal cannot reach the terminals 30 and 30', if only the plate 22 is submitted to the action ofa magnetic flux, since it is not transferred to the terminals 10, 10 by the plate 2. In order to fulfill the conditions of transmission, it is thus necessary to supply a control pulse to the control winding 5 and a control pulse to the control winding 5'. These two pulses may succeed to one another in an arbitrary manner and each core, the control winding of which has received a pulse, retains its remanent magnetic induction, so that an arbitrary time may elapse between the pulses. I f'the two cores exhibit a remanent magnetic induction, two different pulses are also necessary to interrupt the transmission from the terminals 9, 9 to the terminals 30, 30. When a first erasing pulse is applied to the erasing windings 4, the corresponding split portion of the upper left-hand lateral branch of eachcore constitutes an apparent air-gap, so that themagnetic flux through the left-hand outer limb of each core is interrupted. However, a magnetic flux continues to flow through the right-hand outer limb of each core, so that the field strength of the magnetic flux through each plate 2 or 22 is only reduced, but not substantially eliminated. The cores being made up of soft magnetic material having a rectangular hysteresis loop, the reduction of the magnetic flux through each plate only amounts to a few percent, so that the transmission from the terminals 9, 9' to the terminals 30, 30 is maintained. If an erasing pulse is subsequently passed through the other erasing windings 4', the magnetic circuit through the centre limb of each core is almost completely interrupted, so that the remanent magnetic induction in each core is substantially eliminated and transmission from the terminals 9, 9' to the terminals 39, 30 can no longer take place.

The sequence of the control pulses applied to the control windings 5 and 5' is unimportant and a second or further control pulse applied to a winding which has already received a control pulse of the same polarity after the last erasing pulse has no consequence. The sequence of the erasing pulses supplied to the erasing windings 4 and 4' is neither important and such a pulse can only have any effect if an erasing pulse has not yet been applied to these windings, after the end of the last control pulse. in order to bring about transmission be tween the input and output terminals, it is thus necessary to supply at least one control pulse to the winding 5 and at least one control pulse to the winding 5, and for interrupting a transmission it is likewise necessary to apply at least one erasing pulse to the windings 4 and at least one erasing pulse to the windings 4. If, an erasing pulse is applied, for example to the windings 4, between the two control pulses the second control pulse has the effect of magnetizing one of the cores, for example the core 21, 21, 21", while only one half of the other core is still magnetized. The second control pulse nevertheless brings about a transmission, but a single erasing pulse applied to the windings 4 then sulfices to interrupt this transmission, the left-hand half of the core 21, 21, 21" ultimately remaining magnetized. until a new erasing pulse is supplied to the windings 4. Consequently, two different erasing pulses are always required to erase the last control pulse received.

Starting from the embodiment shown in FIGS. 7 and 8, it is, of course, possible to design a gating device with three or more alternative transmission requirements by arranging three or more control windings and, if desired, three or more erasing windings on the core 1, 1'. Starting from the embodiment shown in FIGS. 9 and 10, it is likewise possible to design a gating device with three or more cumulative transmission requirements. For example, a device with three cumulative requirements might be constituted by three four-limbed cores, three plates with magneto-electric transmission properties connected incascade, three control windings and three groups of each three erasing windings.

The limit frequency at which a transmission due to the Hall effect still takes place is, for example, of the order of 10 c./s. for germanium, while the magnetic resistance variation of bismuth decreases to one half at a frequency of about 0.3 10 c./s. The gating devices according to the invention are thus capable of transmitting and, if desired, amplifying comparatively high frequencies.

, The described gating devices have the combined properties of a memory and of a switch and, furthermore, except the'embodiment shown in FIGS. 5 and 6, they bring about a certain amplification of the signal transmitted. They are applicable in all those cases in which such combined properties may be useful, more particularly in control, test and other automatic installations and in computers. In such applications, the input signals are mostly pulses which have to be transmitted or not and the controland erasing-pulse sources are often constituted by central sources of so-called clock pulses, that is to say by sources providing at predetermined timeintervals pulses of likewise determined length, polarity and amplitude.

What is claimed is:

l. A pulse actuated gating memory device comprising a magnetic circuit having a narrow air-gap, said magnetic circuit including a magnetic storage core member capable of storing information by means of its residual magnetization, winding means coupled to said storage member for establishing a desired state of residual magnetizatiou in said storage member, erasing means coupled to said storage member for establishing in the core a condition of local saturation thereby eliminating any residual magnetization, a plate-like member mounted in said airgap so as to be traversed by the magnetic field produced in the magnetic circuit by the said state of residual magnetization in said storage member, and a pair of electrodes coupled to opposed surfaces of the plate-like member and arranged so that a line connecting them extends in a direction transverse to the said magnetic field, said plate-like member possessing an electric property that varies as a function of a magnetic field traversing the plate-like member, whereby the output signal derived at the electrodes is controlled by the said magnetic field traversing the plate-like'member.

2. A pulse-actuated gating memory device comprising a magnetic circuit having a very narrow air-gap, said magnetic circuit including a magnetic storage core member capable of storing information by means of its resid ual magnetization, winding means coupled to said storage member for establishing a desired state of residual magnetization in said storage member, erasing means comprising a winding coupled to said core by way of an aperture in the Wall of said core for establishing therein a condition of local saturation thereby eliminating any residual magnetization, a plate-like member mounted in said air-gap so as to be traversed bythe magnetic field produced in the magnetic circuit by the said state of residual magnetization in said storage member, a first pair of electrodes coupled to opposed surfacess of the platelike member and arranged so that a line connecting them extends in a direction transverse to the said magnetic field for introducing a signal, said plate-like member possessing an electric property that varies as a function of a magnetic field traversing the plate, and a second pair of electrodes coupled to opposed surfaces of the plate-like member and arranged so that a line connecting them extends in a direction transverse to both said magnetic field and the line connecting said first pair of electrodes for deriving the said signal in a condition dependent upon the strength of said magnetic field.

3. A pulse-actuated gating memory device comprising a closed magnetic circuit having a very narrow air-gap, said magnetic circuit including a magnetic storage core member capable of storing information by means of its residual magnetization, control winding means coupled to said storage member for establishing a desired state of residual magnetization in said storage member, erasing means comprising a winding coupled to said core by way of an aperture in the wall of the core for establishing therein a condition of local saturation thereby eliminating any residual magnetization, a Hall effect plate-like member mounted in said air-gap so as to be traversed by the magnetic field produced by the said state of residual magnetization in said storage member, and two orthogonal pairs of electrodes coupled to opposed surfaces of the plate-like member and arranged so that lines connecting each pair extend in a direction transverse to the said magnetic field, whereby signals may be introduced and derived from said device and controlled by the state of residual magnetization established in said storage member.

4. A pulse-actuated gating memory device comprising a closed magnetic circuit having a very narrow air-gap, said magnetic circuit including a magnetic storage core member capable of storing information by means of its residual magnetization, control winding means coupled to said storage member for establishing a desired state of residual magnetization in said storage member, erasing means coupled to said core for establishing therein a condition of local saturation thereby eliminating any residual magnetization, a magneto-resistive plate-like member mounted in said air-gap so as to be traversed by the magnetic field produced by the said state of residual magnetization in said storage member, and av pair of electrodes coupled to opposed surfaces of the platelike member and arranged so that a line connecting 9 them extends in a direction transverse to the said magnetic field, whereby signals may be introduced and derived from said device and controlled by the state of residual magnetization established in said storage member.

5. A pulse-actuated gating memory device comprising a closed magnetic circuit having a narrow air-gap, said magnetic circuit including a magnetic storage member capable of storing information by means of its residual magnetization, control winding means coupled to said storage member for establishing a desired state of residual magnetization in said storage member, erasing means coupled to said storage member for altering the said state of residual magnetization, a magnetic-field-responsive, electrical-condition-variable, plate-like member mounted in said air-gap so as to be traversed by the magnetic field produced by the said state of residual magnetization in said storage member, two orthogonal pairs of electrodes coupled to opposed surfaces of the plate-like member and arranged so that lines connecting each pair extend in a direction transverse to the said magnetic field, two pairs of terminal means connected to said two electrode pairs, a first resistor connecting together one electrode of each pair, and a second resistor connecting together the other electrodes of each pair, said resistors having values at which signals can be selectively transmitted bilaterally between the terminals depending upon the direction of the magnetic field through the plate-like member.

6. A device as set forth in claim wherein the platelike member has a symmetric shape relative to the electrode pairs, and the first and second resistors have the same value.

7. A pulse-actuated gating memory device comprising a closed magnetic circuit having a narrow air-gap, said magnetic circuit including a magnetic storage member capable of storing information by means of its residual magnetization, control winding means coupled to said storage member for establishing a desired state of residual magnetization in said storage member, erasing means coupled to said storage member for altering the said state of residual magnetization, a magneto-resistive plate-like member mounted in said air-gap so as to be traversed by the magnetic field produced by the said state of residual magnetization in said storage member, a pair of electrodes coupled to opposed surfaces of the plate-like membet and arranged so that a line connecting them extends in a direction transverse to the said magnetic field, three additional impedances forming a bridge circuit with the diagonal of said bridge circuit, and means for deriving a signal across the other diagonal of the bridge.

8. A pulse-actuated gating memory device comprising plural closed magnetic circuits each having a very narrow air-gap; each of said magnetic circuits including a magnetic storage core member capable of storing information by means of its residual magnetization, control winding means coupled to said storage member for establishing a desired state of residual magnetization in said storage member, erasing means comprising a winding coupled to the core by way of an aperture in the wall of the core for establishing therein a condition of local saturation thereby eliminating any residual magnetization, a magnetic-field-responsive, electrical-condition-variable, plate-like member mounted in said air-gap so as to be traversed by the magnetic field produced by the said state of residual magnetization in said storage member, and two orthogonal pairs of electrodes coupled to opposed surfaces of the plate-like member and arranged so that lines connecting each pair extend in a direction transverse to the said magnetic field; means for introducing a signal to one pair electrodes of one plate-like member; means connecting the other pair of electrodes of said one plate-like member to a pair of electrodes of another plate-like member; and means for deriving the signal from the other pair of electrodes of said other plate-like member; whereby the establishment of residual magnetization in all the storage members is a pre-condition to transmission of the signal from the introducing to the deriving means. i

9. A device as set forth in claim 8 wherein means are provided interconnecting the erasing windings whereby a common erasing pulse is operative in all the magnetic circuits.

10. A device as set forth in claim 8 wherein each magnetic circuit includes two parallel magnetic paths with a common path, the control winding means and plate-like member are coupled to the common path, and separate erasing means are coupled to each of the parallel paths.

References Cited in the file of this patent UNITED STATES PATENTS 2,649,569 Pearson Aug. 18, 1953 2,649,574 Mason Aug. 18, 1953 2,708,219 Carver May 10, 1955 2,802,953 Arsenault et al. Aug. 3, 1957 2,818,556 Lo Dec. 31, 1957 2,862,184 Longini Nov. 25, 1958 FOREIGN PATENTS 705,248 Great Britain Mar. 10, 1954 784,129 Great Britain Oct. 2, 1957 

